Components

Purpose of this Article

The purpose of this article is to determine how much fuel one should take while going on backpacking excursions. One should take into account the number of days spent in the backcountry, the types of cooking the fuel is needed for (and other uses), and the number of people in the party. We'll cover some of these in the article. This information is merely to help the logistical planning of trips.

Testing components:

Environmental factors:

Altitude: 500ft

Miscellaneous:

The included aluminum heat shields were placed under and around the stove, helping to conserve and reflect heat, and serve as a wind barrier.
The bottle was continually pressured to maintain maximum fuel flow.
The throttle was wide open at 1/2 a turn.

Fuel Consumption & Cooking Facts

Fuel Consumption at ~500 ft:

It takes 8 minutes to boil 3 qt of water, and
It takes 2 minutes 40 seconds to boil 1 qt of water
The stove burned for a total of 30 minutes, and consumed 3.0 oz in that time.

Cooking Facts:

A traditional dehydrated meal for 2 people needs 20 oz (2.5 cups) of water to cook.
A mug of coffee needs, we'll assume, 10 oz of water per person.
A bowl of oatmeal needs 2 oz of water per person.
Total water needed for cooking each day per person is 32 oz.

NOTE: Please come up with your own daily needed boiled water amount, and calculate accordingly, as this will change based on the cooking needs of your the group.

One person having oatmeal and coffee for breakfast and splitting one dehydrated meal between lunch and dinner would consume 32 oz per day.

the Assumption

Scenario >500ft:

Let's assume we're hiking with a group of 4, and we are all sharing the Whisperlite stove.

Our altitude is below 500ft.

We cook 3 times a day, boiling 128 oz each day between all 4 members.

We do not use a fire to cook with, and use the stove for every meal.

The group would use approximately 1.11 oz fuel per day.

This would get us to 9 days using a standard 11 oz bottle, or 18 days using the 20 oz.

Scenario 10,000ft:

Same scenario as above, but at 10,000 ft.

We cook 3 times a day, boiling 128 oz each day between all 4 members.

The group would use approximately 1.02 oz of fuel per day.

This would get us to 10 days using a standard 11 oz bottle, or 20 days using the 20 oz.

Conclusion

The difference between fuel consumption at elevation between sea level and 10,000 feet is negligible. Boiling water at 10,000 feet is approximately 7-9% more efficient than boiling at sea level. However, it is important to note that food cooks much, much slower at elevation, because of the lower temperature of boiling water. This test/article assumes that you do need a continual heating surface for cooking, but rather that you use the boiled water to cook food in a separate thermos-like container (such as the aluminum packaging that store-bought dehydrated meals are packaged in).

Although one should take environmental factors into concern, such as elevation, outside temperature and water temperature, and the fact that you can't squeeze every last ounce of fuel from the bottle, we can conclude that just one small 11oz bottle will last a small group a little over a week in the wilderness.

I will test more in the future using different fuels (diesel and gasoline) and using different stoves (MSR Pocket Rocket), and I will also take elevation into account, to give you a more detailed picture of how much fuel you need to take on your next excursion.

You wrote "Boiling water at 10,000 feet is approximately 10% more efficient than boiling at sea level"

If your objective is simply to boil water, that is technically correct. But if cooking I don't think it accurate to say it is more efficient at altitude. Water boils at a lower temperature at altitude, so all you are seeing is the impact of not heating the water as much. If you heated the water for the same length of time at sea level and added it to your oatmeal just before it boiled you'd have the same result with respect to cooking your food and use the same amount of fuel as at altitude... and your food would be the same termperatute (instead of hotter when you are at sea level).

BTW- to reply to a comment, just use the reply link on the right, rather than posting a new comment.

The objective is not to see efficiency, but rather to see precisely how much fuel is needed for a given trip to help with logistical planning. Honestly, I had been curious to see how much fuel I needed on trips, because although I had experience backpacking, I wasn't sure how many days, realistically, fuel would last. I revised the article to include the objective, so hopefully the goal is clear now.

Very good article indeed, but explain to me something: How did my photo appears on SP first page and when we open the article my photo isn't there anymore, not even linked to the article?
Crazy stuff...
Great text, very informative btw.
Cheers
Paulo

Does anybody still use cups, ounces and quarts? (I think you mean *fluid* ounces, right?) When planning for water consumption I think in liters - and for fuel I'm often interested in grams, especially if I'm considering propane.

A footnote to others regarding fuel consumption: In my experience when camping over 10,000 feet and using the MSR Simmerlite, a 375ml container of white gas will provide enough fuel for one cup of coffee each morning and one two-serving dehydrated meal each evening for a seven to eight day duration. I use a bit of extra fuel with the following technique: After placing the boiling water into the foil container for a dehydrated meal, I'll place another couple of ounces of water in the pan and bring to a second boil with the foil container sitting in the water before shutting down the stove in an effort to better cook the meal. Then I'll let the meal remain in the pan and on the shut-off burner until ready to eat to keep the meal as hot as possible. I'm always using very cold water, but have no idea of the exact temperature. Back when I switched from the Whisperlite, I realized the Simmerlite is not as fuel efficient as your article would suggest. Thanks!

Rather than this, I wrap the meal in my sleeping bag or put some clothes around it to keep it warm. Keeps the meal hot (enough so that I have to wait for it to cool when I open it 10-12 minutes later) and doesn't need the extra fuel. Just an idea.

Liked your article, you mentioned you wanted to do some more testing. I have an idea have you considered melting snow when winter hiking or climbing high? It would be interesting to see how much fuel you need.

I also carry a Wisperlite with an 11-oz tank.
But my situation is different in winter.
I like to melt snow during the day for tea, and later for dinner. The energy requirement to melt the snow is probably the same again, as to boil a pot of water.
Then when I cook a freeze-dried dinner, I must melt the snow, boil the water, and cook the stuff.
Nonetheless, I've never come home with an empty tank. I've never known how much fuel I use -- just lucky I guess.

Depends on what season you climb in, if you just boil water (most climbers do) and how many meals you are eating. For summer: using Whisperlite and only boiling water for two meals a day (for two people) I use 4.5 oz. of fuel max per day. Winter use: same two meals and two people, but melting the snow and using MSR XGK 6oz a day, max.
This is based on some 30 years of using MSR white gas stoves. The brand new ones are a bit more efficient, so if you have a brand new Whisperlight International or the new high altitute MSR white gas stove, the consumption is a bit (less than 1oz) less. Works everytime.